<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>页面2</title>
</head>
<body>
	<a href="demo03.html"></a>
	<button id="back">后退</button>
</body>
</html>
<script>
	var backBtn = document.getElementById("back");
	backBtn.onclick = function(){
		console.log(history,history.length);
		//后退一个页面，效果同浏览器的后退按钮
		history.back();
	}
</script>